TNT (2,4,6-trinitrotoluene, also called .alpha.TNT), as conventionally manufactured by nitration processes from toluene and mixed acid as starting materials, contains significant proportions (usually about 4%) of undesired, unsymmetrical isomers. The standard industrial procedure for removing these isomeric impurities is to treat the crude TNT with aqueous sodium sulfite ("sellite"), which reacts with the reactive nitro groups in the meta or 3 -position and produces a waste sellite solution containing a mixture of sodium 2,4-dinitrotoluene-3 and -5 sulfonates.